nail notch

[Bill Armstrong]

I just began making folding knives and am curious as to the best way to make the nail notch in the blades. Have experimented with several techniques only to ruin a fairly good blade.

[Christopher Price]

The notch, or "Nail Nick" is best done with a sharp punch made for the job, and done before hardening. A little touch-up grinding will take out any bulge from the work, and you should end up with a pretty professional looking feature.

 

Best of luck.

[Alan Longmire]

I use a dovetail cutter on a lathe with a milling attachment.  Some guys use a reshaped stone wheel for a dremel tool.  If you punch it in, do it hot.  That's the way the old timers in Sheffield did it.  But they were a lot better than I am!  

 

If you use the reshaped stone wheel, put the dremel in a vise and gently push the blade onto the stone, with the blade clamped to a backing board of some kind so it can't get away from you.  Every time I tried to do it the other way around I ended up with a ruined blade.  

[Al Massey]

Other way is after the basic forging and prior to HT, curve it laterally around the horn of the anvil and then clamp it in a vise when cool and cut it in with a half-round file and then straighten out the blade. You should have a nice nail nick tapering in width towards each end, no problem.

 

[Gerhard Gerber]

On 5/11/2022 at 8:37 PM, Al Massey said:

Other way is after the basic forging and prior to HT, curve it laterally around the horn of the anvil and then clamp it in a vise when cool and cut it in with a half-round file and then straighten out the blade. You should have a nice nail nick tapering in width towards each end, no problem.

 

Not like I've extensively researched the subject, but for sure first time I've heard about that method, interesting!  Wouldn't trust my skills to get the blade straight again.

 

Since this is the beginner section, my method on my one and only folder was "real men don't need a nail nick" 

[Brian Dougherty]

2 hours ago, Gerhard Gerber said:

Since this is the beginner section, my method on my one and only folder was "real men don't need a nail nick" 

 

Well, that will make sure you don't leave the spring too stiff which is another common beginner mistake

 

[Gerhard Gerber]

36 minutes ago, Brian Dougherty said:

 

Well, that will make sure you don't leave the spring too stiff which is another common beginner mistake

 

Well you got me in one, you need dry hands and considerable hand strength to open that one 
BTW, was busy with several including two from your design, not completely done profiling all the bits when the lot ended up on the shelve for about a year.  Since realized I'd lost track of the steels I'd used, spark test didn't get me anywhere.

(sorry for the slight hi-jack)

[Dick Sexstone]

Called a fly cutter

[Alan Longmire]

Thanks, Dick, I had forgotten about those!

[Alan Longmire]

Since the 1/2" dovetail cutter I have is almost, but not quite, big enough, I think I'll get this combo:

 

https://www.mscdirect.com/product/details/08252017

 

and this bit:

 

https://www.mscdirect.com/product/details/02603124.  If the M2 is too brittle, I'll get the M42 for $10 more.

[Alan Longmire]

Necrothread arise!

 

I finally tried the fly cutter.  Once I figured out how to grind the thing, it will make a nail nick of any radius with ease, provided I slow the lathe enough.  I put it in low and engaged the back gears to reduce it to around 20 rpm, which works great.

 

 

Same point geometry as the dovetail cutter, but just a single point and about 1/20 the price.

[Dick Sexstone]

You have me stumped Alan…..how are you regulating the depth of cut?

[Alan Longmire]

Downfeed.  There's a milling attachment on that 1941 Atlas lathe. 

[Alan Longmire]

I guess it's actually upfeed, since I'm raising the table into the bit... but you get the idea.  It's not just a fly cutter in a lathe. 

[Dick Sexstone]

Ah that explains it…..Cool Machine……

[Alan Longmire]

And here's the end result on that blade after rough grinding:

 

 

That's about a 3.5" blade with the fly cutter set at about a 5/8" radius for what would be a 1.25" diameter cut.  Looks much better than trying to climb mill with the 1/2" dovetail cutter!

[Gerhard Gerber]

Very neat result Alan